Why Choose the Unitronics M91-2-UA2 Micro PLC with Integrated HMI?
The Unitronics M91-2-UA2 is a highly capable Micro PLC with integrated text-based HMI, designed for industrial automation applications requiring digital control, analogue processing, temperature monitoring and analogue output functionality within a single compact controller. As part of the proven Unitronics M91 series, it combines PLC control, operator interface capabilities and onboard I/O, helping reduce panel space, wiring complexity and installation costs.
Featuring a built-in 2-line, 16-character LCD display and a robust 15-key keypad, the M91-2-UA2 enables operators to monitor processes, adjust operating parameters and perform diagnostics directly from the controller. This integrated design eliminates the need for a separate HMI while maintaining a simple and cost-effective automation platform.
With 10 digital inputs, 2 configurable analogue/temperature inputs, 10 transistor outputs and 2 analogue outputs, the M91-2-UA2 is ideally suited to process automation, temperature control, OEM machinery, water treatment systems and industrial monitoring applications. The controller also supports PID control, MODBUS communications and local I/O expansion for enhanced flexibility.
Key Advantages
Integrated PLC and operator interface in one compact controller.
2-line LCD display with built-in keypad.
10 digital inputs and 2 configurable analogue/temperature inputs.
10 transistor outputs including PWM functionality.
2 analogue outputs for process control applications.
Supports thermocouple temperature measurement.
Built-in RS232 and RS485 communications.
Supports MODBUS networking and industrial integration.
Expandable up to 150 I/O points.
Key Features
Unitronics M91 Micro-OPLC platform.
2-line × 16-character STN LCD display.
15-key membrane keypad.
10 digital inputs.
2 configurable analogue / thermocouple inputs.
10 PNP transistor outputs.
2 analogue outputs (0-10 V, 4-20 mA).
1 high-speed counter input up to 10 kHz.
2 PWM outputs.
RS232 and RS485 serial communications.
Auto-tune PID control with up to 4 loops.
Real-time clock with battery backup.
MODBUS RTU protocol support.
I/O expansion support up to 150 points.
Technical Specifications
Manufacturer: Unitronics
Series: M91
Model: M91-2-UA2
Product type: Micro PLC with integrated HMI
Power supply: 24 V DC nominal
Operating voltage: 20.4 to 28.8 V DC
Digital inputs: 10
Analogue / temperature inputs: 2 configurable inputs
Thermocouple support: Types B, E, J, K, N, R, S, T
Digital outputs: 10 transistor outputs
Analogue outputs: 2
PWM outputs: 2
High-speed counter: 1 × 10 kHz, 32-bit
Display: STN LCD, 2 lines × 16 characters
Keypad: 15 keys
Communication ports: RS232 / RS485
Protocol support: MODBUS RTU, OPC
Program memory: 36 KB virtual ladder memory
Database capacity: 1024 integers
Protection rating: IP65 / NEMA 4X when panel mounted
Operating temperature: 0°C to 50°C
Mounting type: Panel or DIN rail mounting
Ideal for Process and Temperature Control
The Unitronics M91-2-UA2 is specifically designed for applications requiring both measurement and control functions. Its configurable analogue inputs can be used for standard process signals or thermocouple temperature monitoring, while the integrated analogue outputs allow direct control of drives, valves, actuators and process equipment.
Combined with PID control, transistor outputs and communication capabilities, the controller delivers a complete automation platform for industrial systems. The integrated display and keypad provide local monitoring and control without requiring additional operator interface hardware.
Typical Applications
Temperature control systems.
Water and wastewater treatment plants.
Industrial process automation.
HVAC and environmental control systems.
Pump and pressure management applications.
Food and beverage processing equipment.
OEM machinery and equipment.
Building management systems.
Technical Specifications
IP Rating
IP65
Series
M91
Product type
Micro PLC with integrated HMI
Power supply
24 V DC nominal
Operating voltage
20.4 to 28.8 V DC
Digital inputs
10
Analogue / temperature inputs
2 configurable inputs
Thermocouple support
Types B, E, J, K, N, R, S, T
Digital outputs
10 transistor outputs
Analogue outputs
2
PWM outputs
2
High-speed counter
1 × 10 kHz, 32-bit
Display
STN LCD, 2 lines × 16 characters
Keypad
15 keys
Communication ports
RS232 / RS485
Protocol support
MODBUS RTU, OPC
Program memory
36 KB virtual ladder memory
Database capacity
1024 integers
Protection rating
IP65 / NEMA 4X when panel mounted
Operating temperature
0°C to 50°C
Mounting type
Panel or DIN rail mounting
Frequently Asked Questions
What is the Unitronics M91-2-UA2 used for?
The M91-2-UA2 is used for industrial automation applications requiring machine control, analogue processing, temperature monitoring and analogue output control.
Does the controller support thermocouple inputs?
Yes. The configurable analogue inputs support multiple thermocouple types including J, K, T, E, N, R, S and B.
How many outputs are available?
The controller provides 10 transistor outputs and 2 analogue outputs for machine and process control applications.
Does the M91-2-UA2 support PID control?
Yes. The controller includes auto-tune PID functionality supporting up to four independent control loops.
Can the controller be expanded?
Yes. The M91-2-UA2 supports local I/O expansion modules and can be expanded up to approximately 150 I/O points depending on system requirements.
Trusted by Industrial Automation Professionals
Unitronics M91 Micro-OPLC controllers are widely used across industrial automation, utilities, OEM machinery and process control sectors, delivering reliable PLC functionality, integrated operator interaction and flexible control capabilities within a compact platform.
IP Rating
IP65
Series
M91
Product type
Micro PLC with integrated HMI
Power supply
24 V DC nominal
Operating voltage
20.4 to 28.8 V DC
Digital inputs
10
Analogue / temperature inputs
2 configurable inputs
Thermocouple support
Types B, E, J, K, N, R, S, T
Digital outputs
10 transistor outputs
Analogue outputs
2
PWM outputs
2
High-speed counter
1 × 10 kHz, 32-bit
Display
STN LCD, 2 lines × 16 characters
Keypad
15 keys
Communication ports
RS232 / RS485
Protocol support
MODBUS RTU, OPC
Program memory
36 KB virtual ladder memory
Database capacity
1024 integers
Protection rating
IP65 / NEMA 4X when panel mounted
Operating temperature
0°C to 50°C
Mounting type
Panel or DIN rail mounting
No documents available for this product.
Delivery
We offer fast UK delivery on all stocked items. Orders placed before 3pm Monday to Friday are eligible for next-day delivery.
Standard delivery: 2–3 working days
Next-day delivery: available on in-stock items when ordered before 3pm
Express options available — contact us for details
Returns
If you need to return an item, please contact our sales team within 30 days of receipt. Items must be returned unused in their original packaging.
Our service agreements are built to support long term procurement relationships. By working closely with engineering teams and procurement departments, we help streamline purchasing processes while ensuring consistent access to critical components and sourcing support when it matters most.
Priority sourcing and supply support
Flexible payment terms for qualifying organisations
Support for engineering, maintenance, and operations
500 +
Stock lines ready to ship
1,000 +
Same day dispatches
3500 +
Customers supported
28
Trusted Manfacturers
● frequently asked questions
Common questions about our products and support
At Led Controls Ltd we help engineers source the right automation and control gear with confidence. below are quick answers to what we are asked most often.
What product ranges do you supply
We supply all leading manfacturers in our industry. we offer next day delivery on most poplour products.
Can you help specify the correct part?
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Do you have stock for urgent orders?
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
What are your delivery times and costs?
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
What about warranties, returns and faulty items?
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
LED Controls is a specialist distributor of factory automation and industrial controls, supplying OEMs, machine builders, panel builders and end users throughout the UK and worldwide. As a trusted UK distributor for many of the world’s leading automation manufacturers, we provide industrial control products, technical expertise and bespoke automation solutions backed by outstanding customer service.
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...